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Currently i am working on simple ECG circuit (electrocardiograph) using simple sound card input to view the wave forms.

Required materials :
LM324N – Quad op-amp
100k resistor
1k Resistor
sound card
some copper coins

So heres how you get started:
Construct the following circuit

yes you got it right, the circuit is very simple.

Now grab some copper coins or any metallic surface, attach some wires to it and those wires will go to the + and – of the opamp as shown in circuit.

I would highly recommend that you put those electrodes on your chest.

Download the software Goldwave, and get started. Turn on your circuit, connect the leads on your chest. Start recording on the software, you should see sudden spikes on your screen in the recording software. Probably that you will see a lot of noise. But the spikes will be visible coming out from noise.
Record for around a minute or so. After recording there is a option for low pass filter. Select cut off frequency of around 40Hz, and you will be able to see those spikes remain intact and noise getting reduced significantly.

I got something like this when i did this experiment:

You can find the main article and full project documentation by swharden here:

Really nice blog, a lot of interesting stuff out there, also i am thankful to SWharden for helping me out when I was trying this out. I aim on working more on circuit in coming few months.

My main aim is to get a clean ECG waveform combined with a pulse oximeter.

NOTE: Building your first ECG will get you confused about a lot of things. It is not easy to identify ECG waveform when you are doing it for the first time. A small reference book is highly recommended for you.

This book has a lot of great information and I found it really very useful in my project.

And there is this reference book which helps in analyzing the ECG waveforms. This book describes various symptoms that could be diagnosed after studying the ECG waveform. This book has made ECG diagnosis much simpler for those not having medical background.

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Salil is an electronics enthusiast working on various RF and Microwave systems. In his free time he writes on the blog, talks over ham radio or builds circuits. He has Yaesu FT2900R VHF transceiver, FT450D HF transceiver and a TYT UV8000E Handheld transceiver.

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